Generator, replace or not

[Ski in NC]

Riverguy- I looked into the Polar DC genny, turns out it is not an inverter based unit like the Honda. It is simply an AC PM alternator with simple rectifiers. Voltage output is regulated by the control system changing engine speed. No active electronic control on the genny side of it. Add more load, volts naturally drop, control system adds rpm to compensate.

And yes, a boat AC or heat pump unit can move several times the Btu equivalent of the power consumed. Depends on temperature of air and temp of water. Further apart in temps and performance drops. A 16kBtu unit with water pump and fan typically draws about 12-16amps.

 

[River Cruiser]

Had a problem with my Westerbeke 8.0. The 3 cylinder mitsubishi wouldn’t start, compression was low. I had the marina remove and replace, I rebuilt it after finding rings stuck by soot. I sent out head, injectors and injection pump. Head needed some valves and new seats also replaced guides. I bought parts and gaskets from a tractor dealer. The marina replaced the mounting platform before installing generator. The total cost was around $2000.00. I also replaced the bearing on the generator shaft, it was just about to fail with catastrophic results for the generator end. The engine failure cost less than the cost would of been if that bearing had failed.

 

[cafesport]

Looks like this thread has devolved into over three subjects in less than 2 pages. To recap I would rebuild the genny. If I wanted to go gennyless and still have ac, cat daddy found the boat show gem I was referring to earlier. It’s new patented technology, a DC variable speed 24 VDC compressor. It ran a 16k btu unit for 9 hours in a booth using a single 300 amp 24volt LBP 8d battery. An in water display boat had 39 degree air at the outlet vent using the same unit and you could definitely run it off solar down here in Miami or the Bahamas.

 

[Riverguy]

Riverguy- I looked into the Polar DC genny, turns out it is not an inverter based unit like the Honda. It is simply an AC PM alternator with simple rectifiers. Voltage output is regulated by the control system changing engine speed. No active electronic control on the genny side of it...

Ski, you are correct that the PolarPower DC generator does not have an inverter or control system >>integrated into the unit<< like a Honda, but that isn't what I was trying to say.

What I meant to convey here is that an inverter will ultimately be required to make DC into (usable) AC. In the end it will >>function<< like a Honda inverter generator, meaning that the engine speed/output will vary with the load.

It's also true that the Polar Power generator 'natively' produces AC (albeit very high frequency AC, utterly unusable in 'raw' form) and subsequently turns that into DC (rectifier bridge). This is actually true of >>all<< brushless generators, so the back-end of the Polar-Power unit is more accurately termed an "alternator". You may recall hearing the artifacts of high-frequency AC-to-DC conversion as 'alternator whine' if you ever installed an audiosystem into a car with an older or a defective alternator.

re: "It is simply an AC PM alternator with simple rectifiers"

Which is exactly what you will find in any inverter-generator, except for one thing...the real magic in the Polar units is in the new generation of ultra-powerful rare-earth magnets that make these things produce so much power with so little weight.

Details are here: https://polarpower.com/products/dc-alternators/ac-vs-dc/

Here is what a typical system will look like:

 

[denverd0n]

No Denver, you misunderstand.

Okay. Thanks for the explanation. I did misunderstand.

 

[DDW]

I do have DC air conditioning on the sailboat. It is a low capacity unit, not going to cool the main cabin of a power boat in Florida conditions, but it will run overnight, even a couple of days on a normal sized battery bank. The main use is to cool the stateroom for sleeping at night. Smallish cabin, about 5 Kbtu output, draws about 18A on 24V. In the stateroom this will lower the temp 1 deg/min while running. Another 5 Kbtu unit in the main cabin struggles on a 90 deg day. But it does dehumidify.

Bottom line is, if you want the AC you are used to, fix or replace the genset.

 

[hjorgan]

Like Forrest Gump, "I love my Genny".
I replaced an older Phasor with a Nextgen.
Have been happy with the new genny, and the support folks are great!
They are out of Jacksonville, Fl.
NEXT GENERATION POWER ENGINEERING INC.

 

[bridaus]

I spoke with this guy at the Miami boat show last week. Interesting stuff, seems to be a good quality product. If you use the generator budget for lithium batteries and electrical upgrades, it might work. No affiliation here, it seems this might be what the OP was looking for.

www.tmdmarine.com


Rafe

Any idea on pricing?

 

[DavidM]

Why would you want a 24V DC diesel generator to power an expensive (with a titanium heat exchanger among other stuff) 24V A/C when for about the same money (or less) than the DC generator you can replace your genset or rebuild it to power your conventional marine A/C system directly plus have power for a shore power charger, water heater, microwave, etc that all run on 120V AC.


David

 

[Arch]

In my case it is simply a question of air conditioning. KaJen, 36 ft. Marine Trader, has 800 Ah main bank fed by 1,600 watts of solar. The only reason the boat has been plugged into shore power is for air conditioning for the last two years. Have not run genny at all. In Florida and Bahamas 9 months of the year, full time live aboard I do not feel the need for air con at anchor.
Arch

 

[armando]

I have a 30 years old Onan 7 KW. And I use to repair and keep it. I have thought many times to change it but I have not done it when comparing new versus repaired.
And I think it is not a good idea substitute it for a bank of batteries and a converter. The Geny not only charge batteries, it helps you if you need and extra power. You feel more secure with it.

 

[bykpjfk]

Having just gone through this drill, I can add a little. Pulled my 20 year old 9kw out to overhaul. Boat jumped on plane without the 600 pounds sitting in the stern. Sold the genny, replace the forward A/C with a 6K btu unit that would operate from my inverter and bought more AGM GC batteries and headed to the Bahamas with a trusty Honda 2K as backup. Works good for a night, but after that the little Honda simply won't power the main A/C and have anything left to heat water, charge house batteries, etc.

Boat is at the yard having her bottom done, and then they will drop in a new Phasor 4.5kw unit (~300lbs). Within reason, you just can't get around having a reasonable size genset on board.

 

[JOY-SEA]

I have a Kohler 5 E generator on my cruiser
Only has 225 hours , built 2003 , gas
We never stay on hook , When we travel stop as transient having dock side / water
Under power we never stay in cabin using a/c ,
Started gen set often
Months ago I am at dock , Electric not plugged in . Started gen set , Running ruff
Sounded like it was starving for fuel , After few moments I happened too look up from cabin , Huge cloud of black smoke coming from all openings under deck
Smoke was so sever looked like boat was on fire , SCARY . Surprised nobody came running from marina ???????
Seems my stator motor windings is grounding , According too the GUY , lucky I closed could have started a fire .
THIS GEN SET IS MAKING ME CRAZY
A large piece of equipment not working does not sit well with me
Almost better not having then a non working gen set
Not easy , too remove Port engine has too come out then gen set
Quotes $$$$ $ 1200 too pull & install engine
Rebuilt gen set $ 5500 ,. AND that was from CL gen shops which usually does not turn out well
Gen shop indicates these gen sets are old , old technology , burn lots of gas , Rebuilding getting parts , could be an issue , PUSHING NEW , BUT new codes & fabrication
could cost $ 13,000 thousand
Boaters traveling long term must get these items fixed , The seldom trip boater like myself , Makes no sense .
Has become an issue , trying too sell boat. Buyers want working gen.
Never getting what we want for boat then add in cost of a new generator ? Means I have too lower my asking price 10 thousand .

I have gotten around , purchased a large power inverter , I can make coffee , power small appliances , TV .
Many have purchased portable gen sets , Honda , Harbor Freight , 2800 watts quiet running ,
We all know about fumes , and safety , putting far away on a swim platform or on bow far away from cabin as possible .
A old gen set in engine room gives off fumes , just as un safe .
A must for the full time boater having alternate power , the occasional water traveler maybe a portable could work
BTU's on my a/c is 9000 . Refrigerator runs a/c d/c
I can purchase a Honda 2800 , plug in dock side , take home as back up

 

[Cheer men]

Why don’t you look at the Efoy system, I removed my generator and have a large battery bank... 12 6v batts,solar panels and the Efoy to top up the batteries. No maitainance,noise and runs off methanol

 

[clyde]

captdj...so...without a genset, other than with the main engine, how will you charge the batts? my old onan kinda went south last yr, after some fone calls, i found a local that could fix it!...clyde

 

[Tugalert]

I had a problem with my RV gen. The Cummins folks told me that at $185.00 a hour it should take 7 hours labor plus parts. I told them to check out the fuel pump. Guess what? They charged me 1 hour labor and parts for a total cost of $305.00. If you know a little about engines they can't cheat you. BTW for years I owned outboards, riding mowers, etc and did my own upkeep.

 

[dave52]

I replaced an old onan with 600 watts of solar and 10 115 amp deep cycle batteries. Still need Honda gas generator to top batteries off everyday at anchor. I have 7 cu ft of refrig and 7 cu ft of freezer (ac/dc).

It all works real well, but solar and wind are an 85-90% solution.

We are considering installing a 3-5 kw diesel because of convience, resale and ability to run heat or ac if desired. Probably $8-10k.

Now we have a top shelf marine solar system, $3-4K, $1k Honda2.8kw , $2000 in batteries and $2k inverter.

 

[clyde]

tugalert...i talked to a friend, that had a friend, was lucky, found a guy that new theory, and mechanicle, he gharged $50 an hr, [total $350] found the rectifier was shot, cummins couldnt find one anywhere in parts search, so i talked to a special cummins parts person, he gave me a coupla part numbers, called amazon, and they had them...they were $10 each, cummins wanted $80 each, amazon sent to many, now i have4 spares!! also replaced a poorly put together exhaust system, that over the years caused me a lot of problems with back pressure, also, put on an external fuel pump, wired it to the onan system, now runs betterthan ever!!

 

[clyde]

tugalert...i also found a good place for some onan parts, like the salt water pump, etc...called ASSOCIATED MARINE..cummins wanted $750 for a new pump, associated had the same pump, $280, i think, spare impellor, and shipping was free!...clyde

 

[clyde]

dave52...a close friend put a honda 3000, with a built in starter, put it in a sound proof box, and a hole for exhaust...works great! has enuff amps to run his 40 amp shore charger...clyde

 

[dave52]

Correct my Honda runs my 40 amp charger, water heater and really and all outlets no problem. Just noisy without the soundproof box and have to handle/store to much gas. And your will be discounted $10k at resale.

 

[bostew]

As others have noted... unless you can reach out and shake hands with a connecting rod from the engine room, a rebuild would be the best course of action, IMHO.

What would determine if it could be rebuilt. I’m in the same situation I just bought a mainship with a 6.5KW NL genset. Only 120 hours on it and a big sell point. 2015 installed. Ran great twice for ten minutes during the survey. I didn’t need it for about a month and it wouldn’t turn over. First we thought bad battery. Replaced, no luck. Called in Norther lights rep. He said it was locked up. They let it set with marvel mystery oil thru the injectors, still locked up. 1k to tell me it’s locked they want another 1k to take the heads off and tell me if it can be rebuilt. They also said it was installed by an unqualified person.
Specifically:
1. the exhaust is too low vs the exhaust riser outlet.
2. there is no loop coming out of the waterlift
3. The clamshell covering the exhaust outlet points down rather than aft.
All this contributes to water easily finding its way into the cylinders.

I feel like if I put another 1k in this unit I’m throwing it in the trash. Am I wrong? Any advice.

 

[DavidM]

Here are several scenarios and the equipment needed. Every one is different so see how your needs fit into one of the following.

1. Casual one night anchor out, always back at dock the next day.

This type of boater just needs a decent size house bank, maybe 2 GC batteries at 220 Ah. That will cover the overnight needs of almost anyone. No solar, no genset.

2. Frequent anchor out but low DC usage

This guy is a perfect candidate for 300 watts of solar and the same moderate size battery bank as above. 300 watts of solar will provide about 100 Ah of power on a sunny day which should cover moderate needs. 220 Ah of house battery capacity will carry him through a cloudy day.

3. Heavy DC use (big fridge) frequent anchor out

This boater could go two ways. One would be a large,500+ watts of panels and a large house battery bank. Another would be a moderate house bank with a 3-5 Kw genset for recharging, hot water heating, microwave, etc.

4. Heavy DC use, casual anchor out and needs air conditioning

This guy needs a genset to run his air conditioning, but if it is 16,000 btu max he can get by with a cheaper NextGen 3.5 Kw unit as long as he manages loads carefully, ie no hot water heating while A/C is running. The NextGen is relatively noisy and light duty but is several thousand $ cheaper than a NL.

5. Frequent anchor out, maybe liveaboard, needs air conditioning

In this case I would pick a heavy duty, 1,800 rpm genset like the NL, but add a 100-200 watt solar panel to top off his house battery bank each day.

What kind of boater are you? I probably missed someone but I bet 95% of us will fall into one of these catagories.

David

 

[bostew]

Gen is dead aw lord the gen is dead

Yes that sounds about right for me .
1 a year maybe to learning and cruising the Chesapeake bay and rivers goal unless it’s beautiful and cool to be at a marina for a night or to. A/c is a must at night.showers at marina . Medium fridge needs to last till batteries can be charged. During the day we would be outside in the breeze. Or at dock looking for to do stuff. We are in Calvert marina Solomon’s md. Very pretty place.
I keep seeing something called a generator head I assume from reading it is set up and pullied to one of the engines. Could that be used mainly to charge batteries and in an emergency run the ac for a bit. Hour or Two.

 

[CapnCrunch]

As someone said, the problem with running an a/c on batteries/inverter is that, while you could prolly install enough batteries to run the unit overnight, but you'd have to run the engines a considerable amount the next day to recharge them. Kinda defeats the purpose. You could do what I and many other "blowboaters" do - use your batteries for the normal loads and a small genny for the heavy stuff. My boat has a 16,000btu Webasto marine unit which I run using a Honda 2000i genny and an Easystart 364 "soft starter." The soft starter is @$300 but it ramps the compressor up in 4 stages rather than the one usual single 54amp (in my case) jolt. Otherwise the a/c would overload the genny. We only run the a/c at night (to keep the gas usage down) and open the ports etc during the day and circulate air with dc fans. We also run the genny in the mornings long enough to make coffee and breakfast and heat some water (usually @ 1 hr). The trickiest part for most sailboats is finding enough space for the solar panels, but you may not have that problem.

 

[Mike Lowthian]

replacing generator

I am replacing my 10 kw generator. I have agreed on the price of the unit with the vendor but he wants $6,000 for the labour which I find very high? Access is reasonable so no real problem there. Can anyone comment on the labour cost? Thanks,

 

[Gotwex]

The future is here

Came across this article and it kind of answers the OP question. Many of the replies to the original question fail to mention the new (to recreational boating) technology of air conditioning inverter compressors. Their low draw make many of the proposed "no gen" set ups mentioned in this thread a reality.

I'm going to post this in a new Thread as well. I think many of TF members would be very interested in this technology.

https://www.passagemaker.com/techni...ddqCbCiWvqfmcdV7t89z-1Hc-Uoo0w&_hsmi=70238631

 

[BIG CAT]

I am replacing my 10 kw generator. I have agreed on the price of the unit with the vendor but he wants $6,000 for the labour which I find very high? Access is reasonable so no real problem there. Can anyone comment on the labour cost? Thanks,

First thing is what is the labor rate. What's the scope of work? What is the travel distance to the boat? Man power needed to remove the old one and install the new one?

 

[FoxtrotCharlie]

We just replaced our 30 yr old Westerbeke (not generating) with a Kohler 9K in a soundshield - takes up half the space of the old one. Cost to remove old gennie, install new one, wire it up, run new fuel lines, new oil drain line...was about $4,300. Add in another $1,400 for installing completely new exhaust 25' line for the gennie. Turner Marine, Mobile. Very satisfied with quality of work.

 

[Riverguy]

Marketing malarkey...

Came across this article and it kind of answers the OP question. Many of the replies to the original question fail to mention the new (to recreational boating) technology of air conditioning inverter compressors. Their low draw make many of the proposed "no gen" set ups mentioned in this thread a reality.

I'm going to post this in a new Thread as well. I think many of TF members would be very interested in this technology.

https://www.passagemaker.com/techni...ddqCbCiWvqfmcdV7t89z-1Hc-Uoo0w&_hsmi=70238631

Nonsense. Quoting from the Passagemaker article:


"Draw is 10 percent less than that of more traditional systems..."


10% is not a game changer, not even close. Reading the fine print, it does not even appear that 10% is a realistic claim. The efficiency gains stated are 100% related to startup compressor draw. In other words -- 'let's use a bigger capacitor'. Even the measly 10% number appears to be contrived.


The laws (First and Second) of thermodynamics are still in effect. Yes Virginia, air-conditioning (which is essentially the removal of heat from the interior) still requires more energy than the solar heat that is bearing down on the exterior.


If this crap from Webasto sounds like marketing-malarkey to you, congratulations. You have good ears. It is marketing malarkey.